Radially focusing lens

[libov]

Hi Michael,

I'm trying to simulate a radially focusing lens using QUAD or KQUAD with RADIAL=1.

The problem is, apparently the RADIAL option has no effect for KQUAD element.
Would you expect this?

Attached are two figures, QUAD.jpeg and KQUAD.jpeg, illustrating this.
The left plots in each file are for RADIAL=0, the right ones for RADIAL=1.
For QUAD element everyting is as expected (focusing/defocusing for R=0 and focusing/focusing for R=1, while for KQUAD it's focusing/defocusing for both RADIAL=0 and RADIAL=1)

The other problem (this was the original reason why I tried KQUAD): if I use QUAD and RADIAL=1 in optimisation, elegant crashes... If I take the option out, everything is ok. I tried KQUAD with RADIAL=1 and it won't crash. Perhaps exactly because this option has no effect?

Thanks in advance for any hint!

EDIT: attaching also the crashlog, if that helps.

Slava

[michael_borland]

Slava,

This is a bug in the twiss parameter computation for KQUAD. The fix will appear in the next release.

If you build from source, you can use the attached file to get the fix.

Thanks for reporting the bug.

--Michael